So, early this Saturday morning on my way home driving on the N1 the dashboard battery light comes on. There were no signs of power loss nor lights dimming as has been described in some forums (beams were on as it was still dark). Drove all the way home fine with no issues but the light stayed on all the way. Parked the car and went to bed.
Later today, after having breakfast at around 12:30, I decide to investigate. So got out the old volt meter and checked the voltage on the battery, which was at around 12.2v so no problem with the battery. Started the car and the voltage drop to around 11.8v. I confirmed these figures using both the volt meter on the battery and the OBC menu 9. As i switched on additional items (ac, radio, lights), with the car running, the voltage continued to drop. At this point, I sort of concluded that the alternator is gone as there was clearly no charge at the battery. Locked the car and went to do some reading on forums.
After reading through as many threads as possible, I sort of concluded that it could be the voltage regulator or the fact the the alternator should just be replaced considering the effort anyway.
So decided to pull the car into the garage and deal with it during the weak. In doing so I obviously bring up menu 9 on the OBC and all of a sudden the alternator is now charging at around 14.0v but the battery light is still on. So I pull the car into the garage, turn the car off and restart it. The battery light turned of for a few seconds this time but now the alternator was over charging when the revs climbed. At idle it would stay around 14.7v but as I rev the engine, it would climb to as high as 17.7v. Also, the warning lights on the dashboard would also come on as i climbed through the revs including the radio switching of. So i decided to let the car idle for a while and then as the engine warmed up i noticed that even at idle speed the alternator was now charging at around 15v. at this point i decided to turn everything of as I didn't want to fry any of the electrics in the car. You never know :-) I confirmed these reading again using the volt meter directly on the battery.
So to conclude, I think is comfortable to say that the voltage regulator has seen better days as clearly the alternator has no problems charging. I'm not sure which model alternator is installed as I have not had a chance to get my hands dirty but this is a job I would like to tackle myself but am afraid that I go out and buy a VR and it turns of the alternator is gone or something worse.
Please let me know your thoughts. I hope I have added enough detail but if not please ask away.
Car details: 2004 e46 320i exclusive with just over 125k. The only extras are the xenon lights package. Bought this car from a colleague with just over 95k over a year ago and must say, being my first BMW, I am enjoy the car. So far had to replace power steering pump, which I ended up doing myself as it happened in the first week of this year and I couldn't find a decent mechanic (That I can Trust) that was open and I was defiantly not going to pay the dealers. Also, about three months ago, i decided to only fill up with BP 95 and a few weeks later my fuel gauge stopped working (It would pretty much stay stuck at full tank all the time). Not sure if it's was coincidence, but over time it seems to have sorted itself out. At the time I was tempted to reset the cluster.
Later today, after having breakfast at around 12:30, I decide to investigate. So got out the old volt meter and checked the voltage on the battery, which was at around 12.2v so no problem with the battery. Started the car and the voltage drop to around 11.8v. I confirmed these figures using both the volt meter on the battery and the OBC menu 9. As i switched on additional items (ac, radio, lights), with the car running, the voltage continued to drop. At this point, I sort of concluded that the alternator is gone as there was clearly no charge at the battery. Locked the car and went to do some reading on forums.
After reading through as many threads as possible, I sort of concluded that it could be the voltage regulator or the fact the the alternator should just be replaced considering the effort anyway.
So decided to pull the car into the garage and deal with it during the weak. In doing so I obviously bring up menu 9 on the OBC and all of a sudden the alternator is now charging at around 14.0v but the battery light is still on. So I pull the car into the garage, turn the car off and restart it. The battery light turned of for a few seconds this time but now the alternator was over charging when the revs climbed. At idle it would stay around 14.7v but as I rev the engine, it would climb to as high as 17.7v. Also, the warning lights on the dashboard would also come on as i climbed through the revs including the radio switching of. So i decided to let the car idle for a while and then as the engine warmed up i noticed that even at idle speed the alternator was now charging at around 15v. at this point i decided to turn everything of as I didn't want to fry any of the electrics in the car. You never know :-) I confirmed these reading again using the volt meter directly on the battery.
So to conclude, I think is comfortable to say that the voltage regulator has seen better days as clearly the alternator has no problems charging. I'm not sure which model alternator is installed as I have not had a chance to get my hands dirty but this is a job I would like to tackle myself but am afraid that I go out and buy a VR and it turns of the alternator is gone or something worse.
Please let me know your thoughts. I hope I have added enough detail but if not please ask away.
Car details: 2004 e46 320i exclusive with just over 125k. The only extras are the xenon lights package. Bought this car from a colleague with just over 95k over a year ago and must say, being my first BMW, I am enjoy the car. So far had to replace power steering pump, which I ended up doing myself as it happened in the first week of this year and I couldn't find a decent mechanic (That I can Trust) that was open and I was defiantly not going to pay the dealers. Also, about three months ago, i decided to only fill up with BP 95 and a few weeks later my fuel gauge stopped working (It would pretty much stay stuck at full tank all the time). Not sure if it's was coincidence, but over time it seems to have sorted itself out. At the time I was tempted to reset the cluster.